Each law journal has submission guidelines that authors must follow when submitting their manuscripts. Do not assume you know the guidelines you must comply with - check the guidelines for every journal you are considering.
One major difference between Canadian and American law journals is Canadian journals generally require authors to submit manuscripts on an exclusive basis, meaning you must submit your manuscript to one journal at a time. Most American law journals do not require exclusivity, allowing authors to submit to multiple journals simultaneously. American legal authors often submit to more than a dozen journals at the same time.